This invention relates to an apparatus and method for the volumetric measuring and dispensing of ice from a holding bin. The machine is desirably used in an environment for dispensing a high volume of soft drinks of several sizes.
Restaurants and food-service establishments with high volumes of beverages need to accurately measure both the amount of beverage and the amount of ice dispensed. Such establishments have ice machines and ice dispensers for this purpose. Ice dispensers typically have a hopper or bin for storing a quantity of ice bodies, desirably in the form of ice cubes, crushed ice, cracked ice or flaked ice. The ice dispenser usually has an agitator in the hopper to prevent the ice from melting into a solid lump. The agitator may also function to force the ice out of the hopper during a dispensing operation through a gate that controls the ice leaving the bin through a dispensing opening. When the gate is opened and the agitator rotated, ice exits the bin, drops down a chute, and is dispensed into a cup. Operation of the dispenser is typically controlled either by a cup-operated lever or a hand-operated button. In a common type of dispenser, ice will pour from the bin for as long as the lever or button is pressed, and the ice flow stops when the button or lever is released.
Other types of ice dispensers are used in establishments with very high volumes, where it is desired to dispense automatically a measured quantity of ice. The dispenser is typically on a timer circuit, such that the timer causes a door or opening to the ice bin to open, and dispensing occurs for a preset period of time in response to actuation of an operating lever or button. Dispensing systems such as these have several advantages, including simplicity, ease of adjustment and the flexibility to accommodate several different ice portions by pressing one of several operating levers or buttons to vary the timed dispensing period. A major disadvantage is that the accuracy with which selected quantities of ice may be dispensed is extremely limited, since the flow rate of ice out of the dispensing gate varies with the amount of ice in the bin, with the orientation of the agitator paddles or blades with respect to the bin opening, and with the speed of rotation of the agitator. There is also a good deal of variation in the flow rate of the ice bodies as they leave the bin, depending on their size, their friction interaction among themselves and with the walls of the bin and dispensing chute, and their temperature. As a result, there can be great differences in the amounts of ice dispensed from one drink to the next, and from one day to the next.
The problem of measuring the flow of solids is a difficult one, even when dealing with xe2x80x9cfriendlyxe2x80x9d solids such as grains or powders. Some of the xe2x80x9cusualxe2x80x9d methods available for storage and flow of solids are simply not appropriate to the problem of moving ice in a fast-paced food service environment. Pneumatic conveyors or conveyor belts are simply not a feasible solution to the flow of ice in a fast-paced food service environment. The many problems that are encountered with the measurement of solids flow usually encourage solutions in the form of secondary measurements, such as the time of flow, or in many cases, load cells on small portions of a conveyor or flow system. While these methods are satisfactory, they may be very expensive, as with a load cell, or subject to other vagaries, such as with a timed cycle. If anything happens to delay the flow, whether of a powder or an ice mass, a timed cycle will not yield an accurate flow.
What is needed is a better way to dispense ice from an ice machine or an ice dispenser in which the volume of ice is measured. What is needed is an ice-dispensing machine that allows a user to select a sized portion of ice over a range of sizes, such as small, medium and large, and which machine will deliver the selected quantity of ice reliably from cup to cup and from day to day.
The present invention meets this need by a unique metering system in which the volume of ice dispensed is measured while it is being dispensed. A micro-controller receives signals from a volume-measuring device, preferably a wheel placed into a chute through which the ice passes on its way from the ice bin to a cup of a user. When a quantity of ice is desired, a user pushes a switch or a touch pad to select the quantity desired. The machine may be activated by placing a cup into a lever-operator once a quantity is selected. A door to a bin containing the ice opens and ice is funneled from the door down a dispensing chute. As the ice falls down the chute, it bears against and rotates a measuring wheel whose axis is desirably below and outside the chute, and whose working blades extend through the bottom and into the chute. The blades are desirably thin so that they cannot interfere with the movement of ice, but thick enough to resist bending by the ice, even larger particles of ice that may come along from time to time.
The working of the wheel is analogous to the operation of a Roots blower in measuring volumes of gas by causing the rotation of a precision impeller in a pipe of known smoothness and diameter, with a gas stream of known density and with a known pressure drop. By working with known conditions, it is possible to measure the flow of a solid, ice, with reasonable accuracy, by using the same principles. These conditions include an ice bin with a known relationship to an ice dispenser and chute. The flow may vary according to the angle between the ice bin and the ice chute, and the relationship of the door to both. The height of the ice above the door and the chute bears directly on the amount of ice that will pour through the door and down the chute. Other variables include the amount of ice in the bin, the speed of agitation, and the angle of repose of the ice within the bin. Yet other variables will include the size of the door, the size or diameter of the chute, the smoothness or roughness of the chute, the size of the ice flake, ice particle or ice cube conveyed, and the temperature of the system. Preferably, the apparatus allows a user to account and adjust for all these and other variables. After an ice dispensing and measuring apparatus of this invention has been in service, and conditions have changed, or the amount of ice desired changes, the preferred apparatus allows changes to the amount of ice dispensed in a reasonably facile manner.
The rotation of the measuring wheel is captured via an optical or other sensor and correlated to a volume, using the diameter of the chute and the amount of rotation. The weight of the ice may also be used to correlate the amount sensed. The volume is controlled by a microcontroller that compares the volume dispensed with the volume selected. When the volume requirement is met, the microcontroller shuts the door to the ice bin and awaits the next customer.
Another aspect of the invention comprises a method of measuring the flow of a solid through the system described above. The method comprises steps of selecting a predetermined amount of ice, activating a flow of ice through a chute according to the predetermined amount of ice, and stopping the flow of ice when the selected amount has been reached. In another aspect of the invention, the ice dispensing unit has inputs and outputs from the microcontroller and the amount of ice dispensed may be varied, less or more, separately, for each of a plurality of volumes of ice desired, such as a small amount, a medium amount, a large amount, or an extra-large amount.
The invention, its features and its advantages will be further understood upon consideration of the following detailed description of various embodiments of the invention taken in conjunction with the drawings.